Disclosed are formulations for providing a therapeutic bioactive polypeptide to injured tissue. Formulations include mineral coated microparticles wherein a polynucleotide is adsorbed to the mineral layer. Other formulations include a carrier including mineral coated microparticles wherein mineral coated microparticles include a polynucleotide. Also disclosed are methods for sustained delivery of a bioactive polypeptide and methods for treating chronic wounds using a formulation for providing sustained delivery of the bioactive peptide.